Coarse reduction impact crushers are employed for breaking rock. A rotor is disposed in the housing of the crusher, which rotor has a preferred operating direction but can be reversed.
The crushing tools employed in the crusher comprise a plurality of impact members. These tools are subject to wear, and therefore are replaceably fixed to the rotor, namely they are fixed in suitable accommodation cavities in the rotor by means of wedges. The wedges are driven into a fixed wedged position by mechanical impact means or hydraulic means. Because the tools (impact members) are subject to wear, they are symmetrically configured, so that when one impact edge experiences excessive wear one need only rotate the impact member in its accommodation cavity and re-fix it, to take advantage of a second, fresh impact edge.
Known means of fixing impact members have certain drawbacks, e.g., when mechanical wedge means are used, dust and fine particles tend to cause the impact members to become jammed, so that they can be rotated or replaced only with difficulty and corresponding expense. Hydraulic fixing systems are costly, because for control purposes the hydraulic lines must be extended to the exterior from the rotating rotor.
The underlying problem of the invention is to refine the known system wherein the impact members are mechanically fixed in their respective accommodating cavities by means of wedges, such that (in the refinement) the wedged configurations or wedges are easily and readily releasable, or may even release themselves when the rotor is stopped.